About RunWebTools
RunWebTools is a library of 108 web tools, 29 in-depth guides, and 22 reference tables, built around one unusual constraint: the work happens on your device, not ours. When you drop a PDF here to merge it, split it, or strip its metadata, that file never leaves your computer. The same goes for the images you resize, the video you trim, the JSON you format, and the text you paste.
Why that constraint matters
Most “free online converter” sites work by uploading your file to a server, processing it there, and handing back a download link. That means a stranger's machine holds a copy of your document — which is a genuine problem when the document is a signed contract, a medical scan, a passport photo, or an export from work.
Modern browsers no longer require that trade-off. The APIs needed to do real work locally — Canvas for pixels, WebCodecs for video, the File and Clipboard APIs, Web Crypto for hashing — are all mature. So the tools here are built as client-side applications: the page ships the code to your browser, and your browser does the work. There is no upload endpoint to leak, no processing queue to breach, and no retention policy to trust, because there is no copy on our side to begin with. You can verify this yourself — open your browser's Network tab and watch a file-based tool run.
A handful of tools genuinely cannot work this way, and we say so on the page rather than hiding it. Live exchange rates, IP address lookup, and the ping test all need to reach the network by definition. Those are the exceptions, and each one names the service it contacts.
Three layers, not just a tool list
A converter that spits out a result but never explains it leaves you exactly as informed as you were before. So the site is organised in three connected layers:
- Tools — 108 utilities across 15 categories: PDF editing, image processing, formatters, encoders, calculators, date and time, device diagnostics, and a browser video editor.
- Guides — 29 long-form articles in 7 topic clusters, explaining the concepts behind the tools: why JSON parsing fails, what EXIF data reveals about a photo, how Base64 actually works, why a monitor shows colour banding.
- Reference — 22 searchable lookup tables for the things nobody memorises: HTTP status codes, MIME types, cron syntax, CSS units, regex patterns, ASCII codes, keyboard shortcuts.
The layers cross-link automatically. Use the JSON formatter and it will point you to the guide on fixing common JSON errors; read that guide and it points back at the tools that apply. The aim is that you leave understanding the problem, not just having a fixed file.
Two ways to use every tool
Each tool works as an ordinary web page, and most also ship as a bookmarklet you can drag to your bookmarks bar. Click it on any website and the tool opens as a small panel on that page — useful for counting or reformatting text without losing your place. The panel is isolated in a shadow DOM so it cannot collide with the host page's styles, it can be parked in any corner, and it remembers where you left it.
How the tools are built and checked
Tools that transform data have their logic written as pure functions, separately from the interface, so the same code can be run and verified outside the browser. The PDF engine, for instance, was validated against real documents before it shipped, and the video editor's export path was checked by decoding its own output frame by frame. We describe the whole process on the how we build and test page, including what we deliberately do not do.
Free, and how that is paid for
Everything is free with no account, no install, no trial, and no feature held back for a paid tier. The site is supported by advertising. Ads are kept out of the working area of each tool, because an interface that tricks you into misclicks is a worse product — and because processing happens locally, we are not paying for a server farm that would push us toward more aggressive monetisation.
Who runs this
RunWebTools is an independent project, not a venture-funded startup or a content farm. It is built and maintained by one developer who kept needing these utilities, kept landing on sites that wanted an upload and an email address first, and decided to build the version that does not ask.
Get in touch
Found a bug, spotted an error in a guide, or want a tool we don't have yet? Corrections are genuinely welcome — head to the contact page or email contact@runwebtools.com. For what we collect and store, see the privacy policy.